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April 9th, 2026 22:48
U4025QW primary daisy chain to U2725QE, no signal
When I use the Dell U2725QE as the primary display, the daisy chain works correctly (laptop -> upstream to the U2725QE and downstream to the upstream port of the U4025QW).
However, when I configure it the other way around—connecting the upstream cable to my laptop and from the downstream U4025QW with a cable to the upstream port of the U2725QE—the U2725QE does not receive a signal.
When both monitors are connected directly to my laptop through upstream connections, they function properly. Settings: I have the MST enabled on the U2725QE and on the U4025QW Thunderbolt daisy chain selected on optimized. Display resolution is on it’s maximum 5k and 4K and both limited to 60 Hz. The Thunderbolt cables are from Apple and quality wise; new and good.
I cannot use the U2725QE as the primary display. This is due work, I am required to use a outdated application that does not support 4K resolution or higher. When running this program (on a daily basis) it tends to freeze, forcing me to turn off one of the monitors. The U2725QE is positioned vertically in portrait mode besides the U4025QW.
The backup solutions, if nothing else work, is to connect both monitors separately cables to my laptop. However these monitors are quite expensive, and this is not how it should work.
DELL-ChrisM2
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April 10th, 2026 17:02
Is the provided AC power adapter connected to the Lenovo ThinkPad L16 port #2?
Be sure that you are connecting the monitor to port #3 on the Lenovo ThinkPad L16.
When U4025QW is Primary, test U4025QW Menu --> Display --> Thunderbolt Daisy Chain Standard.
(edited)
DELL-ChrisM2
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April 10th, 2026 14:25
While testing =
* The unknown Laptop should have its AC power adapter connected
* Use only the provided in the monitor box Thunderbolt 4 cables
* Both monitors should be set at default Landscape
* What specific Laptop model and operating system?
* Since using Thunderbolt daisy chain, MST is turned on automatically. But having U2725QE Menu --> Display --> MST On is also fine
Unknown Laptop Thunderbolt --> U2725QE 1.0 m Thunderbolt 4 cable --> U2725QE #7 Thunderbolt 4 Upstream port
U2725QE #6 Thunderbolt 4 downstream port --> U4025QW 1.5 m Thunderbolt 4 cable --> U4025QW #6 Thunderbolt 4 Upstream port
U2725QE ports page 13
Unknown Laptop Thunderbolt --> U4025QW 1.5 m Thunderbolt 4 cable --> U4025QW #6 Thunderbolt 4 Upstream port
U4025QW #5 Thunderbolt 4 downstream port --> U2725QE 1.0 m Thunderbolt 4 cable --> U2725QE #7 Thunderbolt 4 Upstream port
Test both U4025QW Menu --> Display --> Thunderbolt Daisy Chain Optimized and Standard
U4025QW ports page 15
Nacho24nl
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April 10th, 2026 16:47
@DELChrisM2
* What specific Laptop model and operating system?
- Lenovo thinkpad L16 gen 1, windows 11 processor: ryzen pro 5.
* Use only the provided in the monitor box Thunderbolt 4 cables
* Both monitors should be set at default Landscape
- I did set them both to landscape, also in the beginning i only used/tried it with tbt cables provided.
- I can’t get a signal trough the dell u2725qe when the dell u4025qw is setup primary. However when I turn on and of the dell, I can hear the windows sound that it connects.
Lenovo downstream to upstream port dell u4025qw and downstream to upstream port dell 2725qe.
i just found out: if i turn off the dell u4025qw with the daisy chain mentioned above, the dell u2725qw will turn on and get a signal trough. What does this mean? Settings in monitor or laptop is to weak??
(edited)
Nacho24nl
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April 10th, 2026 17:40
It worked; I had always assumed that port 2 was the Thunderbolt port. This assumption arose because I never use my adapter; at work, it is always connected to port 2 via the docking station.
I sincerely appreciate your assistance. At the same time, I feel rather foolish.